Various analog circuits, voltage reference circuits for example, suffer from offset error. Offset error results from mismatch of circuit components. For example, in an amplifier, mismatch of differential input transistors can cause the amplifier to produce a non-zero output voltage when the amplifier input voltage is zero. Offset error can detrimentally affect the operation of a circuit receiving a signal that includes an offset voltage.
Attempts are made to minimize offset error in a variety of applications. However, even after compensating for offset error, the factors that produce the offset error can vary with temperature, causing a variation in the offset error with temperature. Such variation is referred to as “offset drift.”